bethke



J. P. BETHKE.

MAGNETIC PULLEY. APPLICATION FILED AUG.23. ma.

1,384, 1 77. 4 Patented July 12, 1921.

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L'P.'BETHKE.

MAGNETIC PULLEY. APPLICATION rlLsn Aumzs. 1918.

1,384,177. Patented July 12, 1921.

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44 n y/$641 '%%43 t w a ttozne g3 UNITED STATES PATENT orrlca.

JOHN P. BETHKE, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO MAGNETIC IMANUFAC- TUBING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

MAGNETIC PULLEY.

Specification of Letters Patent.

Patented July 12, 1921.

Application filed. August 23, 1918. Serial No. 251,104.

T whom it may concern:

e it known that I, JOHN P. BETHKE, a citizen of the United States, residing at Milwaukee, county of Milwaukee and State of Wisconsin, have invented new and useful Improvements in Magnetic Pulleys, of which the following is a specification.

My invention relates to improvements in magnetic pulleys.

The object of my invention is to provide means for maintaining a rapid circulation of air through such pulleys, whereby the same may be adequately cooled; also to provide means whereby such a pulley may be built up from a series of interlocking units, each unit including a winding and peripheral pole pieces spaced apart and with the winding covered by peripheral bands of non-magnetizable material; also to provide means whereby such a series of units may be adequately supported from a central shaft in spaced relation thereto to provide one or -more annular, air circulation cavities, each alternate unit being supported from adjacent units to avoid the necessity of providing direct supports from the shaft for all of the units.

In the drawings- Figure 1 is a longitudinal, sectional View of a magnetic pulley embodying my invention and composed of a set of three magnetic units.

Fig. 2 is a cross-sectional view, drawn on I line 2-2 of Fig. 1.

Fig. 3 is a fragmentary, sectional view, drawn on line 3-3 of Fig. 1.

Like parts are identified bythe same reference characters throughout the several views. 7 V

The supporting shaft 1 is provided with a collar 2 at one end of the pulley. This collar 2 has an annular notch 3, to which a sleeve 4 is fitted. The sleeve 4: is also fitted to the shaft and keyed thereto at 5.

An annular ring 6, of substantially increased diameter, is supported from the sleeve 1 by a series of radially extending webs 7, which are obliquely positioned and adapted to not only support the ring 6, but

to perform the function of fan blades. The outer surface 9 of the ring 6 is concavely curved along longitudinal planes and forms a seating for'one of the magneticunits, as hereinafter explained.

The collar 2 may be secured to the shaft by any suitable means. In the construction shown, the shaft is provided with a shoulder at 12, against which this collar seats, and at the opposite end of the pulley a similar collar 14 is secured to the shaft and interiorly shouldered to receive a sleeve 15, similar to sleeve 4, and provided with radially extending, obliquely disposed webs 17, similar to the webs 7 and which support a seating ring 18, similar to the ring 6, but oppositely disposed, whereby its concave surface 19 faces inwardly, as is also'the case with the concave seating surface 9 of the ring 6.

These seating rings 6 and 18 support a series of magnetic units, each comprising a steel spool 20 adapted to receive an energizing winding 21, and having end flanges,

which constitute annular pole pieces 22, the

outer surfaces of which form a portion of the periphery of the pulley. The inner faces of these pole pieces are notched to receive a sleeve of nonmagnetizable material adapted to cover the winding 21. The end face 26 of one of the pole pieces is provided with an inwardly facing annular shoulder, and the other pole piece or flange is provided with an outwardly facing shoulder 28, this shoulder being adapted to interlock with shouldered members carried by adjacent portions of the pulley for mutual support. At the respective ends of the pulley, end rings 30 and 31 are employed. The ring 30 has an inwardly projecting flange at its inner margin, notched and fitted to the shoulder 28 of the adjacent spool. The ring 31 has an inwardly projecting flange 34, the inner portion of which is thickened and shouldered to engage underneath the shoulder 27 on the adjacent spool. The intermediate spools have their shoulders 27 engaging shoulders 28 of the adjacent spool throughout the length of the pulley, whereby all the spools are interlocked for mutual support as stated above. Longitudinally extending bolts 38 pass through the core portions 1O of the respective spools and the in ner faces of the cores 10 are rounded at each end, whereby the end spools may be seated upon the supporting rings 6 and 18, the in nerspools being supported from the end spools and from the connecting bolts 38.

With the above described construction, it is obvious that the various elements of my improved pulley may be quickly separated and reassembled, thus enabling me to remove and replace any unit which has be come damaged or in which the winding has been short circuited. Each spool is integrally formed, thus enabling me to provide magnets of maximum intensity.

Air cooling.

The radial webs 7 and 17 at the respective ends of the pulley constitute fans whereby air is driven through the pulley longitudinally. In addition to this, means for cooling the pulley, I have provided a series of radially extending apertures 42 formed by grooving the meeting faces of the interlocking portions of the respective units. The outer ends of these passages or apertures 42 are conically enlarged, as shown at 43, and the inner ends of the passages communicate with the cavities a lunderneath the inter.- locking shoulders of the spools. These cavities 41:4 are, of course, in communication with the space betweenthe spools and the shaft through which the air is being driven by the fan webs 7 and 17.

The belt or apron 45 employed in connection with my improved pulley carries air with it by friction, and on the side where it approaches the pulley, this air is driven into the wedge-shaped space between the belt and the periphery of the pulley. The latter also carries air with it, the quantity of air being increased by reason of the cavities formed by the apertures 42, and, therefore, on the upper side of the pulley, 6., the side of belt approach,) the air is constantly being compressed and forced through the apertures into the cavities 44. On the opposite side of the pulley, the movement of the pulley and belt has a constant tendency to create a vacuum along the line where the belt separates from the pulley, and for a short distance outwardly from said line, along a path taken by the separating surfaces of the belt and the pulley. This causes a rapid movement of air outwardly through the apertures 42 on the lower side of the belt.

It will be observed that the air circulating through the cm ities 44, by reason of the currents passing through the apertures 42, will absorb the heat from a much greater aggregate radiating surface than can be absorbed by the longitudinally moving air currents, and, therefore, effective cooling is greatly facilitated, it being, of course, understood that the heat to be removed by the air currents is generated in the windings of the respective units. It will also be obvious that the radially moving air currents, caused by the passage of air through these apertures 42 inwardly on the upper or belt receiving side of the pulley and outwardly on the lower or belt separating side, tends to produce eddy currents within the cylindrical cavity inclosed by the magnetic units,

thereby greatly increasing the effectiveness of the air in this cavity for heat absorption, since otherwise air following the shaft would not be exposed to the heat radiating from the spools, and the air following the spools would only be momentarily exposed to any heat or radiating surface.

My improved magnetic pulley is adapted to be'utilized in magnetic separators and for all other purposes in which magnetic attraction is to be exerted through the periphery of pulley traversed by a belt or apron.

The energizing windings or coils are connected with each other through cross passages lli and 47 in the spool heads. The spool heads are preferably provided with abutting projections 48 and 49, through which the passages 46 extend, thus protecting the conducting wires from injury, and from exposure to the air currents in the cavities d4. The passages 4L7 are located near the periphery beyond the interlocking shoulders 27 and 28, the arrangement being such that successive spools may be wound in opposite directions in order that the abutting spool heads or pole pieces may be of like polarity. The lead wires 50 and 51 extend inwardly through a longitudinal aperture 52 in the shaft, and radially through suitable aperture 53 either in the webs 7 and 17 at the respective ends of the pulley, or in a single web at one end of the pulley as shown.

I claim 2- 1. A magnetic pulley comprising a hollow magnetic spool having an open end and peripheral perforations, and an exciting coil wound upon said spool.

2. A magnetic pulley comprising a plurality of hollow spools, axially alined, and having a central cavity open at the ends and a plurality of peripheral openings communicating with said cavity, and an exciting coil wound upon each of said spools.

3. A magnetic pulley provided with an interior cavity, and an apertured periphery adapted to permit air to enter and leave the cavity, said pulley having openings at its respective ends adapted to permit air to enter the cavity, and fan wings in said openings adapted to permit air circulation therethrough.

4. A magnetic pulley comprising the combination of a series of magnet spools, each provided with a winding and arranged end to end with like poles abutting, supporting rings for the end spools, said spools having cavities provided between the adjacent spool. heads, means for clamping the spools together, and means for circulating air through said cavities.

5. A magnetic pulley comprising the com bination of a series of magnet spools, each provided with a winding and arranged end to end with like poles abutting, the Walls of the opposed ends of the spools diverging within the peripheral portions to form cavities, said spools having apertures extending from the outer periphery thereof ,to the cavities, supporting rings for the end spools and means for clamping the spools together.

6. A magnetic pulley including the combination with a pulley provided with energizing windings, and passages extending through the pulley, of a belt extending over said pulley, said passages having their inlets and outlets arranged to utilize the belt to force air through the pulley.

7. A magnetic pulley comprising a shaft, a series of concentric spools each provided with an energizing winding and supported from the shaft with an intervening annular cavity, said spools having interlocking heads for mutual support and having a series of peripheral openings in communication with said cavity whereby both transverse and longitudinal ventilation are secured.

8. A magnetic pulley comprising a shaft, a series of concentric spools each provided with an energizing winding and supported from the shaft with an annular cavity said -spools having interlocking heads partially with the opposing heads of like polarity associated and having peripheral margins shouldered to receive covering sleeves for the windings, and peripheral covering sleeves resting on said shoulders between the heads of each spool.

10. A magnetic pulley provided with passages adapted to freely permit of both transverse and longitudinal air circulatioindue to the rotation of said pulley.

11. A magnetic pulley composed of a series of headed spools disposed end to end and oppositely wound, and means for developing air currents along the inner faces of the spools and portions of their opposing heads.

12. A magnetic pulley having a plurality of elements arranged in axial alinement, each element comprising a magnetic spool having a shallow annular groove formed therein, an exciting winding in said groo e, and means for separately cooling each element, whereby a high current density may be employed and a large magnetic flux produced.

13. A magnetic pulley comprising a shaft, a plurality of magnetic spools mounted thereon, said spools having adjacent concave ends and an opening connecting the concavities, thereby providing free circulation of air about each spool.

In testimony whereof I aflix my signature in the presence of two witnesses.

JOHN P. BETHKE.

Witnesses:

FREDERICK WV. Noun,

0. C. WEBER. 

